The clever macaques have found a genius way to score food. Picture: Peter Mayoh

Primate researchers in Indonesia say a monkey mafia presides over an Indonesian temple, the New York Post reports.

The mischievous macaques — who have deceptively sweet faces — take tourists’ belongings, only returning them in exchange for food, according to New Scientist. They’ve bartered over everything from hats to wads of cash.

Don’t fall for it. Picture: iStockSource:Supplied

Locals have long observed the monkeys’ rude behaviour at Uluwatu Temple in Bali.

Videos from the renowned temple show the animals leaping onto unsuspecting tourists, stealing their stuff and hobbling back to their perches as they await a ransom.

But there’s important science to be gleaned from these aggressive animals, say researchers from the University of Liège in Belgium. Since the Uluwatu Temple is really the only place where monkeys act this way, the behaviour must be learned.

We now what you’re up to now, monkey.Source:Supplied

With each generation, the monkeys have grown bolder and have learned from their parents that if they hold onto the stolen goods, they will get a tasty treat.

The monkeys are actually pretty smart to be able to pull this stunt off over generations, the scientists say.

The clever macaques have found a genius way to score food. Picture: Peter MayohSource:News Limited

Reaching this conclusion was no easy task, either, says lead researcher Fany Brotcorne, a primatologist.

“The monkeys were always trying to steal my hat, my pen, even my research data,” she told New Scientist.

This article originally appeared on the New York Post and was reproduced with permission.